Urinary neutrophil gelatinase-associated lipocalin as biomarker in the differential diagnosis of impairment of kidney function in cirrhosis

Understanding and Treating Hepatorenal Syndrome: Insights from Recent Research

Acute kidney injury (AKI) is a critical and often fatal complication in decompensated cirrhosis, significantly affecting inpatient survival rates. Hepatorenal syndrome (HRS), a distinct subtype of AKI, develops in individuals with advanced cirrhosis and portal hypertension. It is marked by progressive kidney dysfunction, poor prognosis, and frequently causes death before liver transplantation. The pathogenesis of HRS involves vasodilation of the splanchnic vessels, leading to overactivation of the endogenous vasoactive systems, circulatory dysfunction, and reduced renal perfusion, which ultimately impairs glomerular filtration. Recent studies have highlighted the role of systemic inflammation in exacerbating renal damage. Despite these changes, renal histology in HRS usually shows no significant abnormalities, and there is typically no hematuria, proteinuria, or abnormal findings on ultrasound. Common risk factors for HRS include spontaneous bacterial peritonitis, infections, and large-volume paracentesis without albumin infusion. Diagnosing HRS is challenging, particularly in distinguishing it from acute tubular necrosis, due to the absence of specific biomarkers. Treatment primarily involves vasoconstrictors such as terlipressin and albumin, with liver transplantation being the definitive therapeutic option. This review provides an updated understanding of HRS, addressing its pathophysiology, diagnosis, management, and future challenges, based on recent expert consensus.

Urine TIMP2.IGFBP7 Reflects Kidney Injury After Moderate Volume Paracentesis in Patients With Ascites: A Randomized Control Study

Background

Urinary biomarkers may predict acute kidney injury (AKI) in cirrhosis with ascites in a moderate volume paracentesis setting.

Objective

The study aimed to assess the risk and consequence of AKI and its progression in patients with decompensated cirrhosis undergoing paracentesis using a urine test measuring tissue inhibitor of metalloproteinases-2 (TIMP2) and insulin-like growth factor-binding protein 7 (IGFBP7).

Methods

A randomized, controlled trial was performed. All outpatients with decompensated cirrhosis with ascites and diuretic complications were enrolled and randomized into 3 and 5 L paracentesis groups. Serial urine samples were analyzed for TIMP2. IGFBP7 concentration before and after paracentesis.

Results

A total of 90 patients with decompensated cirrhosis were consecutively enrolled during the study period. After screening, 29 patients were enrolled in the 3-L paracentesis group, and 25 patients were enrolled in the 5-L paracentesis group. The mean of the MELD score was 8 ± 1.2. Urine TIMP2.IGFBP7 > 2, rising urine TIMP2, and rising urine TIMP2/urine Cr were shown in patients within the 5-L group for 48% (p = 0.015), 32% (p = 0.049), and 76% (p = 0.010) respectively, indicating a higher incidence of renal tubular injury markers in this group. Urine TIMP2.IGFBP7/1000 > 2 was statistically significant to predict a hemodynamic event (p = 0.002).

Conclusion

In cirrhotic patients with ascites undergoing paracentesis, a 5-L paracentesis volume was associated with a higher incidence of renal tubular injury markers. Trail Registration: The national clinical registration number was TCTR20191116003.

The Kidney and Extracorporeal Therapies in Acute-on-Chronic Liver Failure: What the Nephrologist Needs to Know

In this review, we discuss the pathophysiology and management of acute kidney injury (AKI) in the setting of acute-on-chronic liver failure (ACLF). ACLF is characterised by the occurrence of acute hepatic and/or extrahepatic organ failure, induced by immune dysregulation and systemic inflammation in patients with chronic liver disease. Kidney involvement is common, with AKI occurring in 30% to > 95% of ACLF patients, depending on the definition used. Since there is a lack of kidney biopsy data in these patients, the underlying pathophysiological basis of AKI remains incompletely understood, and systemic inflammation is believed to be the primary driver of organ injury. The management of AKI has been largely extrapolated from studies in decompensated cirrhosis, and there is little data specifically in the ACLF setting. However, available evidence suggests that structural kidney injury is more common in ACLF than in decompensated CLD, and therefore, AKI in ACLF is less likely to respond to volume repletion and vasopressors. Treatment options remain limited for those who are non-responsive to intravenous fluids and vasopressors. Liver transplantation (LT), with or without kidney transplantation, is the definitive treatment for these patients. At present, extracorporeal therapies such as therapeutic plasma exchange and kidney replacement therapies play a supportive role in ACLF as a bridge to LT; however, the optimal timing and dosing remain unclear. While theoretically, extracorporeal therapies have the potential to reverse or halt progression of organ damage in ACLF, there is limited evidence currently.

Prospective validation of the EASL management algorithm for acute kidney injury in cirrhosis

BACKGROUND & AIMS

The management of acute kidney injury (AKI) in cirrhosis is challenging. The EASL guidelines proposed an algorithm for the management of AKI, but this has never been validated. We aimed to prospectively evaluate this algorithm in clinical practice.

METHODS

We performed a prospective cohort study in consecutive hospitalized patients with cirrhosis and AKI. The EASL management algorithm includes identification/treatment of precipitating factors, 2-day albumin infusion in patients with AKI ≥stage 1B, and treatment with terlipressin in patients with hepatorenal syndrome (HRS-AKI). The primary outcome was treatment response, which included both full and partial response. Secondary outcomes were survival and adverse events associated with terlipressin therapy.

RESULTS

A total of 202 AKI episodes in 139 patients were included. Overall treatment response was 80%, while renal replacement therapy was required in only 8%. Response to albumin infusion was achieved in one-third of episodes. Of patients not responding to albumin, most (74%) did not meet the diagnostic criteria of HRS-AKI, with acute tubular necrosis (ATN) being the most common phenotype. The response rate in patients not meeting the criteria for HRS-AKI was 70%. Only 30 patients met the diagnostic criteria for HRS-AKI, and their response rate to terlipressin was 61%. Median time from AKI diagnosis to terlipressin initiation was only 2.5 days. While uNGAL (urinary neutrophil gelatinase-associated lipocalin) could differentiate ATN from other phenotypes (AUROC 0.78), it did not predict response to therapy in HRS-AKI. Ninety-day transplant-free survival was negatively associated with MELD-Na, ATN and HRS-AKI as well as uNGAL. Three patients treated with terlipressin developed pulmonary edema.

CONCLUSIONS

The application of the EASL AKI algorithm is associated with very good response rates and does not significantly delay initiation of terlipressin therapy.

IMPACT AND IMPLICATIONS

The occurrence of acute kidney injury (AKI) in patients with cirrhosis is associated with poor short-term mortality. Improving its rapid identification and prompt management was the focus of the recently proposed EASL AKI algorithm. This is the first prospective study demonstrating that high AKI response rates are achieved with the use of this algorithm, which includes identification of AKI, treatment of precipitating factors, a 2-day albumin challenge in patients with AKI ≥1B, and supportive therapy in patients with persistent AKI not meeting HRS-AKI criteria or terlipressin with albumin in those with HRS-AKI. These findings support the use of this algorithm in clinical practice.

Renal Complications in Portal Hypertension

Acute kidney injury (AKI) is a common complication among patients with decompensated cirrhosis and its development is associated with worse prognosis in terms of survival. Patients with decompensated cirrhosis may develop a unique type of AKI, known as hepatorenal syndrome (HRS-AKI), characterized by marked impairment of kidney function due to haemodynamic changes that occur in late stages of liver cirrhosis. Besides, patients with cirrhosis also may develop chronic alterations of kidney function (chronic kidney disease, CKD), the incidence of which is increasing markedly and may be associated with clinical complications. The aim of this review is to provide the reader with an update of the most relevant aspects of alterations of kidney function in patients with cirrhossi that may be useful for theri clinical practice.

Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Biomarkers in pursuit of precision medicine for acute kidney injury: hard to get rid of customs

Traditional acute kidney injury (AKI) classifications, which are centered around semi-anatomical lines, can no longer capture the complexity of AKI. By employing strategies to identify predictive and prognostic enrichment targets, experts could gain a deeper comprehension of AKI's pathophysiology, allowing for the development of treatment-specific targets and enhancing individualized care. Subphenotyping, which is enriched with AKI biomarkers, holds insights into distinct risk profiles and tailored treatment strategies that redefine AKI and contribute to improved clinical management. The utilization of biomarkers such as N-acetyl-β-D-glucosaminidase, tissue inhibitor of metalloprotease-2·insulin-like growth factor-binding protein 7, kidney injury molecule-1, and liver fatty acid-binding protein garnered significant attention as a means to predict subclinical AKI. Novel biomarkers offer promise in predicting persistent AKI, with urinary motif chemokine ligand 14 displaying significant sensitivity and specificity. Furthermore, they serve as predictive markers for weaning patients from acute dialysis and offer valuable insights into distinct AKI subgroups. The proposed management of AKI, which is encapsulated in a structured flowchart, bridges the gap between research and clinical practice. It streamlines the utilization of biomarkers and subphenotyping, promising a future in which AKI is swiftly identified and managed with unprecedented precision. Incorporating kidney biomarkers into strategies for early AKI detection and the initiation of AKI care bundles has proven to be more effective than using care bundles without these novel biomarkers. This comprehensive approach represents a significant stride toward precision medicine, enabling the identification of high-risk subphenotypes in patients with AKI.

Applying Metabolomics and Aptamer-based Proteomics to Determine Pathophysiologic Differences in Decompensated Cirrhosis Patients Hospitalized with Acute Kidney Injury

A case-control study of 97 patients hospitalized at our institution. We performed aptamer-based proteomics and metabolomics on serum biospecimens obtained within 72 hours of admission. We compared the proteome and metabolome by the AKI phenotype (i.e., HRS-AKI, ATN) and by AKI recovery (decrease in sCr within 0.3 mg/dL of baseline) using ANCOVA analyses adjusting for demographics and clinical characteristics. We completed Random Forest (RF) analyses to identify metabolites and proteins associated with AKI phenotype and recovery. Lasso regression models were developed to highlight metabolites and proteins could improve diagnostic accuracy. Results: ANCOVA analyses showed no metabolomic or proteomic differences by AKI phenotype while identifying differences by AKI recovery status. Our RF and Lasso analyses showed that metabolomics can improve the diagnostic accuracy of both AKI diagnosis and recovery, and aptamer-based proteomics can enhance the diagnostic accuracy of AKI recovery. Discussion: Our analyses provide novel insight into pathophysiologic pathways, highlighting the metabolomic and proteomic similarities between patients with cirrhosis with HRS-AKI and ATN while also identifying differences between those with and without AKI recovery.

Seeing and Sensing the Hepatorenal Syndrome (HRS): The Growing Role of Ultrasound-Based Techniques as Non-Invasive Tools for the Diagnosis of HRS

More than half of patients hospitalized with liver cirrhosis are dealing with an episode of acute kidney injury; the most severe pattern is hepatorenal syndrome due to its negative prognosis. The main physiopathology mechanisms involve renal vasoconstriction and systemic inflammation. During the last decade, the definition of hepatorenal syndrome changed, but the validated criteria of diagnosis are still based on the serum creatinine level, which is a biomarker with multiple limitations. This is the reason why novel serum and urinary biomarkers have been intensively studied in recent years. Meanwhile, the imaging studies that use shear wave elastography are using renal stiffness as a surrogate for an early diagnosis. In this article, we focus on the physiopathology definition and highlight the novel tools used in the diagnosis of hepatorenal syndrome.

Hepatorenal Syndrome in Cirrhosis

Hepatorenal syndrome (HRS) is a form of kidney dysfunction that characteristically occurs in liver cirrhosis. It is characterized by a marked impairment of kidney function in response to circulatory and hemodynamic alterations that occur in advanced stages of liver cirrhosis, aggravated by systemic inflammation and bacterial translocation. The classical definitions of the types of HRS have been recently revisited and 2 forms of HRS have been redefined: the acute form, referred to as acute kidney injury (HRS-AKI), and the chronic form, referred to as chronic kidney disease. HRS-AKI is one of the most severe forms of AKI in patients with cirrhosis and it consists of an abrupt impairment of kidney function, frequently triggered by an infection, appearing in the setting of advanced decompensated cirrhosis. Differential diagnosis with other causes of AKI is crucial because HRS-AKI requires a specific treatment. Differential diagnosis with AKI-acute tubular necrosis may be challenging and kidney biomarkers may be useful in this setting. Treatment of HRS-AKI is based on the administration of vasoconstrictor drugs in combination with volume expansion with albumin. Prognosis of HRS-AKI is poor, and the ideal definitive treatment consists of liver transplantation or simultaneous liver-kidney transplantation. HRS-AKI has a big impact on patients' quality of life. Management of HRS-AKI remains challenging in specific situations such as alcohol-associated hepatitis or metabolic-associated steatotic liver disease cirrhosis. Developing preventive measures for HRS-AKI, improving its early identification, discovering new biomarkers for differential diagnosis, and improving the response to therapy are some of the unmet needs in the field of HRS-AKI.

Urine Liver-Type Fatty Acid Binding Protein; Biomarker for Diagnosing Acute Kidney Injury and Predicting Mortality in Cirrhotic Patients

Objective: To determine impact of urine liver-type fatty acid binding protein (uL-FABP) and urine neutrophil gelatinase-associated lipocalin (uNGAL), which were biomarkers linked to acute kidney injury (AKI), in AKI diagnosis and prediction of 28-day mortality among hospitalized cirrhotic patients. Materials and Methods: We prospectively enrolled hospitalized cirrhotic patients at a tertiary care university hospital between June 2018 and November 2019. The uL-FABP, uNGAL, and plasma NGAL (pNGAL) were collected within 48 hours of admission. Cutoff values of biomarkers for diagnosing AKI derived from receiver operating characteristic (ROC) curve. Logistic regression analysis was used to identify independent factors for 28-day mortality. Results: We enrolled 109 cirrhotic patients in derivative cohort, 41.3% had AKI. Median uL-FABP, uNGAL, and pNGAL levels in AKI group were higher than non-AKI group: 8.1 vs. 2.8 ng/mL (p=0.002), 40.5 vs. 10.1 ng/mL (p<0.001), and 195.7 vs 81.4 ng/mL (p=0.001), respectively. Areas under the ROC curve of uL-FABP, uNGAL, and pNGAL for AKI diagnosis were 0.68, 0.73 and 0.68, respectively. Also, all biomarkers were significantly higher in mortality group. Multivariate analysis showed that the only independent predictor for 28-day mortality was uL-FABP ≥ 4.68 ng/mL (odd ratio 4.15, p=0.02). Conclusion: UL-FABP, uNGAL, and pNGAL are associated with AKI in hospitalized cirrhotic patients. Moreover, uL-FABP ≥ 4.68 ng/mL was a significant independent predictor for 28-day mortality.

Hepatorenal Syndrome Type 1: Diagnosis and Treatment

Hepatorenal syndrome (HRS) is a feared complication in patients with advanced cirrhosis and is associated with significant morbidity and mortality. While recognized as a distinct physiologic condition for well over one hundred years, a lack of objective diagnostic tests has made the diagnosis one of exclusion. Since 1979, multiple sets of diagnostic criteria have been proposed. Though varying in detail, the principal intent of these criteria is to identify patients with severe, functional acute kidney injury that is unresponsive to volume resuscitation and exclude those with structural injury. However, accurate differential diagnosis remains challenging. Recently, multiple urinary biomarkers of kidney injury, including neutrophil gelatinase-associated lipocalin, have been studied as a means of objectively phenotyping etiologies of acute kidney injury in patients with cirrhosis. Along with markers reflecting tubular functional integrity, including the fractional excretion of sodium, injury markers will likely be incorporated into future diagnostic criteria. Making an accurate diagnosis is critical, as therapeutic options exist for HRS but must be given in a timely manner and only to those patients likely to benefit. Terlipressin, an analog of vasopressin, is the first line of therapy for HRS in much of the world and has recently been approved for use in the United States. Significant questions remain regarding the optimal dosing strategy, metrics for titration, and the potential role of point-of-care ultrasound to help guide concurrent albumin administration.

Neutrophil Gelatinase-associated Lipocalin Predicts Short-term Outcomes in Decompensated Cirrhosis With Acute Kidney Injury

Background and aims

Acute kidney injury (AKI) increases mortality in cirrhosis. Early identification of the cause of AKI helps in planning appropriate management. We aimed to find whether neutrophil gelatinase-associated lipocalin (NGAL) can be used to differentiate between different types of AKI in cirrhosis and predict short-term outcomes in patients with decompensated cirrhosis and AKI.

Method

This was a time-bound study in which consecutive hospitalized patients with cirrhosis and AKI were prospectively recruited and managed as per standard care. Acute on chronic liver failure (ACLF) was diagnosed as per the EASL-CLIF Acute-on-Chronic Liver Failure in Cirrhosis (CANONIC) criteria. Urine NGAL was measured by enzyme-linked immunosorbent assay (ELISA) by Epitope Diagnostics Inc. kit (San Diego, USA.) in all patients on admission, and patients were followed up until hospital discharge or death.

Results

A total of 110 consecutive patients (median [range] age: 44 [28-81] years;87.3%were male; ACLF: 71.8%; acute decompensation 28.2%; Model for end-stage liver disease (MELD) 27 [13-46]; Child-Turcotte-Pugh (CTP) 11 [7-15]) with cirrhosis and AKI were recruited. Alcohol was the most common etiology of cirrhosis(64.5%)). Pre-renal azotemia (PRA) was the most common cause of AKI (n = 56). Urine NGAL was significantly elevated in acute tubular necrosis (ATN) (1747 [6-6141] ng/ml than in hepatorenal syndrome (HRS) (379 [33.5-2320] ng/ml; P < 0.0001) and PRA (167 ng/ml [3.34-660]; P < 0.0001). Sixty-four percent patients with ATN, 27.6% patients with HRS, and none with PRA required dialysis. A total of 79.31% patients with HRS and 76% with ATN died. Urine NGAL was significantly higher in patients who required hemodialysis than in those who did not (1733 [243-6141] ng/ml vs 235 [3.34-2320] ng/ml; P < 0.0001). Both urine NGAL (n = 110) and plasma NGAL (n = 90) were significantly higher in patients who died (urine NGAL: -475 [6-6141] ng/ml vs 247 [3.34-2320] ng/ml; P = 0.002;plasma NGAL-950 [94-4859] ng/ml vs 608 [18-3300)]g/ml; P < 0.001). On multivariate analysis, urine NGAL and INR could predict mortality.

Conclusion

NGAL can differentiate between different types of AKI in cirrhosis and predict the need for hemodialysis and mortality in decompensated cirrhosis with AKI.

Acute Kidney Injury and Hepatorenal Syndrome in Patients with Cirrhosis

Acute kidney injury (AKI) is common in hospitalized patients with cirrhosis. Hepatorenal syndrome (HRS) is a type of AKI known as HRS-AKI. It is a severe complication of cirrhosis with high morbidity and mortality. While certain vasoconstrictor medications have been shown to improve HRS-AKI, no clear transplant-free survival benefit has been reported with medical therapies. Patients with HRS-AKI should be considered for urgent liver transplantation evaluation. In this review, we discuss the most recent updates on the definition, diagnosis, and management of AKI in cirrhosis, with special a emphasis on HRS.

Novel prognostic biomarkers in decompensated cirrhosis: a systematic review and meta-analysis

BACKGROUND

Patients with decompensated cirrhosis experience high mortality rates. Current prognostic scores, including the model for end-stage liver disease (MELD), may underperform in settings other than in those they were initially developed. Novel biomarkers have been proposed to improve prognostication accuracy and even to predict development of complications.

METHODS

We performed a systematic review and meta-analysis on novel urine and blood biomarkers and their ability to predict 90-day mortality in patients with decompensated cirrhosis. Secondary outcomes included 28-day and 1-year mortality, and development of acute-on-chronic liver failure, acute kidney injury and other complications. To overcome differences in units, temporal changes in assays and reporting heterogeneity, we used the ratio of means (RoM) as measure of association for assessing strength in predicting outcomes. An RoM>1 implies that the mean biomarker level is higher in those that develop the outcome than in those that do not.

RESULTS

Of 6629 unique references, 103 were included, reporting on 29 different biomarkers, with a total of 31 362 biomarker patients. Most studies were prospective cohorts of hospitalised patients (median Child-Pugh-Turcotte score of 9 and MELD score of 18). The pooled 90-day mortality rate was 0.27 (95% CI 0.24 to 0.29). The RoM for predicting 90-day mortality was highest for interleukin 6 (IL-6) (2.56, 95% CI 2.39 to 2.74), followed by urinary neutrophil gelatinase-associated lipocalin (uNGAL) (2.42, 95% CI 2.20 to 2.66) and copeptin (2.33, 95% CI 2.17 to 2.50). These RoMs were all higher than for MELD (1.44, 95% CI 1.42 to 1.46).

CONCLUSION

Novel biomarkers, including IL-6, uNGAL and copeptin, can probably improve prognostication of patients with decompensated cirrhosis compared with MELD alone.

[Hepatorenal Syndrome]

Hepatorenal syndrome (HRS) is a critical and potentially life-threatening complication of advanced liver disease, including cirrhosis. It is characterized by the development of renal dysfunction in the absence of underlying structural kidney pathology. The pathophysiology of HRS involves complex interactions between systemic and renal hemodynamics, neurohormonal imbalances, and the intricate role of vasoconstrictor substances. Understanding these mechanisms is crucial for the timely identification and management of HRS. The diagnosis of HRS is primarily clinical and relies on specific criteria that consider the exclusion of other causes of renal dysfunction. The management of HRS comprises two main approaches: vasoconstrictor therapy and albumin infusion, which aim to improve renal perfusion and mitigate the hyperdynamic circulation often seen in advanced liver disease. Additionally, strategies such as liver transplantation and renal replacement therapy are essential considerations based on individual patient characteristics and disease severity. This review article provides a comprehensive overview of hepatorenal syndrome, focusing on its pathophysiology, diagnostic criteria, and current management strategies.

Hepatorenal syndrome: Current concepts and future perspectives

Hepatorenal syndrome (HRS), a progressive but potentially reversible deterioration of kidney function, remains a major complication in patients with advanced cirrhosis, often leading to death before liver transplantation (LT). Recent updates in the pathophysiology, definition, and classification of HRS have led to a complete revision of the nomenclature and diagnostic criteria for HRS type 1, which was renamed HRS-acute kidney injury (AKI). HRS is characterized by severe impairment of kidney function due to increased splanchnic blood flow, activation of several vasoconstriction factors, severe vasoconstriction of the renal arteries in the absence of kidney histologic abnormalities, nitric oxide dysfunction, and systemic inflammation. Diagnosis of HRS remains a challenge because of the lack of specific diagnostic biomarkers that accurately distinguishes structural from functional AKI, and mainly involves the differential diagnosis from other forms of AKI, particularly acute tubular necrosis. The optimal treatment of HRS is LT. While awaiting LT, treatment options include vasoconstrictor drugs to counteract splanchnic arterial vasodilation and plasma volume expansion by intravenous albumin infusion. In patients with HRS unresponsive to pharmacological treatment and with conventional indications for kidney replacement therapy (KRT), such as volume overload, uremia, or electrolyte imbalances, KRT may be applied as a bridging therapy to transplantation. Other interventions, such as transjugular intrahepatic portosystemic shunt, and artificial liver support systems have a very limited role in improving outcomes in HRS. Although recently developed novel therapies have potential to improve outcomes of patients with HRS, further studies are warranted to validate the efficacy of these novel agents.

Anesthesia in patients with chronic liver disease: An updated review

Anesthesia in chronic liver disease patients can be challenging because of the medications given or interventions performed and their effects on liver physiology. Also, the effects of liver disease on coagulation and metabolism should be considered carefully. This review focuses on anesthesia in patients with different chronic liver disease stages. A literature search was performed for Scopus and PubMed databases for articles discussing different types of anesthesia in patients with chronic liver disease, their safety, usage, and risks. The choice of anesthesia is of crucial importance. Regional anesthesia, especially neuroaxial anesthesia, may benefit some patients with liver disease, but coagulopathy should be considered. Regional anesthesia provides optimum intraoperative relaxation and analgesia that extends to the postoperative period while avoiding the side effects of intravenous anesthetics and opioids. Pharmacodynamics and pharmacokinetics of anesthetic medications must guard against complications related to overdose or decreased metabolism. The choice of anesthesia in chronic liver disease patients is crucial and could be tailored according to the degree of liver compensation and the magnitude of the surgical procedure.

The Diagnosis and Non-pharmacological Management of Acute Kidney Injury in Patients with Cirrhosis

Acute kidney injury in patients with cirrhosis is quite common, and is seen in up to 50% of patients hospitalized for decompensated cirrhosis. Causes of acute kidney injury include prerenal, renal, or postrenal etiologies. The diagnosis and early institution of nonpharmacologic and pharmacologic management are key to the recovery of renal function. The objective of this review is to provide a practical approach to the use of diagnostic biomarkers and highlight the nonpharmacologic management and prevention of acute kidney injury.

Renal damage in Hepatorenal Syndrome: A still unsolved issue

Acute kidney injury (AKI) is a common complication of cirrhosis, burdened by high morbidity and mortality rates and progression to chronic kidney disease. Hepatorenal syndrome (HRS) is a peculiar type of functional AKI observed in cirrhotic patients with ascites. HRS diagnosis is still clinical, once pre-renal azotemia and intrinsic kidney damage have been excluded by applying well-established and internationally adopted criteria. HRS is considered reversible because of the absence of intrinsic renal damage. However, HRS reversibility has been questioned, due to the lack of response to treatment with vasoconstrictors plus albumin in a relevant percentage of patients and to the persistence of renal dysfunction in HRS patients who underwent liver transplantation (LT). Indeed, LT is the only ultimate treatment, as it solves both liver failure and portal hypertension. Thus, the presence of renal damage in HRS can be hypothesized. In this scenario, neutrophil gelatinase-associated lipocalin (NGAL), one of the most promising biomarkers, may help in characterizing the type of renal injury, distinguishing between HRS and acute tubular necrosis. This review gathers the available evidence in favor and against the presence of structural lesions in HRS in terms of either renal histology and urinary biomarkers with a particular focus on NGAL. The ability to properly characterize which component of renal dysfunction prevails - functional rather than structural - entails a relevant clinical impact for the treatment of these patients, both in terms of medical therapy and liver vs. combined liver-kidney transplantation.

Hepatorenal Syndrome: Pathophysiology, Diagnosis, and Treatment

Hepatorenal syndrome (HRS) is a primarily functional form of acute kidney injury (AKI) that develops in patients with decompensated cirrhosis. The pathophysiologic cascade that leads to HRS begins with pooling of blood in the splanchnic system, resulting in a decrease in effective circulating arterial volume. The definitive treatment of HRS is liver transplantation. When this is not possible, HRS is treated with a combination of vasoconstrictor agents and intravenous albumin. Although the combination of midodrine and octreotide is used in the United States, the recently approved terlipressin, an analog of vasopressin, is likely to become the first-line standard of care.

Intraoperative Renal Replacement Therapy in Orthotopic Liver Transplantation

Acute kidney injury in patients admitted to the hospital for liver transplantation is common, with up to 80% of pretransplant patients having some form of acute kidney injury. Many of these patients start on dialysis prior to their transplant and have it continued intraoperatively during their surgery. This review discusses the limited existing literature and expert opinion around the indications and outcomes around intraoperative dialysis (intraoperative renal replacement therapy) during liver transplantation. More specifically, we discuss which patients may benefit from intraoperative renal replacement therapy and the impact of hyponatremia and hyperammonemia on the dialysis prescription. Additionally, we discuss the complex interplay between anesthesia and intraoperative renal replacement therapy and how the need for clearance and ultrafiltration changes throughout the different phases of the transplant (preanhepatic, anhepatic, and postanhepatic). Lastly, this review will cover the limited data around patient outcomes following intraoperative renal replacement therapy during liver transplantation as well as the best evidence for when to stop dialysis.

Recent advances in pathophysiology, diagnosis and management of hepatorenal syndrome: A review

Hepatorenal syndrome with acute kidney injury (HRS-AKI) is a form of rapidly progressive kidney dysfunction in patients with decompensated cirrhosis and/or acute severe liver injury such as acute liver failure. Current data suggest that HRS-AKI occurs secondary to circulatory dysfunction characterized by marked splanchnic vasodilation, leading to reduction of effective arterial blood volume and glomerular filtration rate. Thus, volume expansion and splanchnic vasoconstriction constitute the mainstay of medical therapy. However, a significant proportion of patients do not respond to medical management. These patients often require renal replacement therapy and may be eligible for liver or combined liver-kidney transplantation. Although there have been advances in the management of patients with HRS-AKI including novel biomarkers and medications, better-calibrated studies, more widely available biomarkers, and improved prognostic models are sorely needed to further improve diagnosis and treatment of HRS-AKI.

Diagnostic and prognostic performance of urinary neutrophil gelatinase-associated lipocalin in patients with cirrhosis and acute kidney injury

BACKGROUND AND AIMS

Acute kidney injury (AKI) commonly occurs in patients with decompensated cirrhosis. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) could help discriminate between different etiologies of AKI. The aim of this study was to investigate the use of uNGAL in (1) the differential diagnosis of AKI, (2) predicting the response to terlipressin and albumin in patients with hepatorenal syndrome-AKI (HRS-AKI), and (3) predicting in-hospital mortality in patients with AKI.

APPROACH AND RESULTS

One hundred sixty-two consecutive patients with cirrhosis and AKI were included from 2015 to 2020 and followed until transplant, death, or 90 days. Standard urinary markers and uNGAL were measured. Data on treatment, type, and resolution of AKI were collected. Thirty-five patients (21.6%) had prerenal AKI, 64 (39.5%) HRS-AKI, 27 (16.7%) acute tubular necrosis-AKI (ATN-AKI), and 36 (22.2%) a mixed form of AKI. Mean values of uNGAL were significantly higher in ATN-AKI than in other types of AKI (1162 ng/ml [95% CI 423-2105 ng/ml] vs. 109 ng/ml [95% CI 52-192 ng/ml]; p  < 0.001). uNGAL showed a high discrimination ability in predicting ATN-AKI (area under the receiver operating characteristic curve, 0.854; 95% CI 0.767-0.941; p  < 0.001). The best-performing threshold was found to be 220 ng/ml (sensitivity, 89%; specificity, 78%). The same threshold was independently associated with a higher risk of nonresponse (adjusted OR [aOR], 6.17; 95% CI 1.41-27.03; p  = 0.016). In multivariable analysis (adjusted for age, Model for End-Stage Liver Disease, acute-on-chronic liver failure, leukocytes, and type of AKI), uNGAL was an independent predictor of in-hospital mortality (aOR, 1.74; 95% CI 1.26-2.38; p  = 0.001).

CONCLUSIONS

uNGAL is an adequate biomarker for making a differential diagnosis of AKI in cirrhosis and predicting the response to terlipressin and albumin in patients with HRS-AKI. In addition, it is an independent predictor of in-hospital mortality.

Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches.

Cirrhosis and Portal Hypertension

Ascites is the most common complication of cirrhosis, with 5-year mortality reaching 30%. Complications of ascites (ie, spontaneous bacterial peritonitis, hepatorenal syndrome, recurrent/refractory ascites, and hepatic hydrothorax) further worsen survival. The development of ascites is driven by portal hypertension, systemic inflammation, and splanchnic arterial vasodilation. Etiologic treatment and nonselective beta-blockers can prevent ascites in compensated cirrhosis. The treatment of ascites is currently based on the management of fluid overload (eg, diuretics, sodium restriction, and/or paracenteses). In selected patients, long-term albumin use, norfloxacin prophylaxis, and transjugular intrahepatic portosystemic shunt reduce the risk of further decompensation and improve survival.

Urine neutrophil gelatinase-associated lipocalin as a biomarker of acute kidney injury and prognosis in decompensated chronic liver disease: A prospective study

BACKGROUND

Acute kidney injury (AKI) heralds deterioration in patients with decompensated chronic liver disease (DCLD). Serum creatinine (sCr), a component of the model for end-stage liver disease-sodium (MELD-Na) prognostic score, has limitations in patients with DCLD. We evaluated the prognostic role of urine neutrophil gelatinase-associated lipocalin (NGAL) in DCLD and its ability to sub-type AKI.

METHODS

Total 147 consecutive patients hospitalized between June 2018 and June 2020 for complications of DCLD were evaluated. Urine NGAL was estimated and demographic, clinical and biochemical parameters recorded at baseline. Participants were followed up till the end of study period or mortality, whichever came earlier. Primary outcomes included all-cause mortality and time to death after index hospitalization. Secondary outcomes included the presence and type of AKI, need for intensive care unit (ICU) stay, length of ICU/hospital stay, in-hospital mortality, development of new-onset/recurrent AKI and recurrent hospitalization after index admission.

RESULTS

Urine NGAL was highest in acute tubular necrosis (ATN), lowest in pre-renal azotemia (PRA) and intermediate in hepatorenal syndrome (HRS-AKI). Urine NGAL (p = 0.0208) was superior to sCr (p = 0.0388) and inferior to fractionated excretion of sodium (FENa) (p = 0.0013) in stratifying AKI. A cut-off of 203.9 ng/mL discriminated between HRS and PRA with sensitivity 77.8% and specificity 68.7%. Urine NGAL correlated with MELD-Na score, need for ICU stay, in-hospital mortality and mortality at three and six months. Two-year survival was significantly lower in patients with urine NGAL > 205 ng/mL. Addition of log-urine-NGAL score did not improve predictive performance of MELD-Na.

CONCLUSION

Urine NGAL could identify AKI sub-types and correlated with short-term clinical outcomes, including mortality.

Renal Insufficiency in Patients with Cirrhosis

Renal failure is one of the most prevalent complications in patients with cirrhosis and is of the utmost prognostic relevance. Acute kidney injury (AKI) in cirrhosis results from a spectrum of etiologies, of which hepatorenal syndrome (HRS) carries the worst prognosis. Correct differentiation of the etiology of AKI in cirrhosis is imperative, as treatment defers substantially. This review summarizes the current diagnostic criteria, pathophysiology, diagnosis, and therapeutic concepts for AKI and HRS-AKI in cirrhosis.

Novel biomarkers of acute kidney injury in chronic liver disease: Where do we stand after a decade of research?

Acute kidney injury (AKI) is a frequently encountered complication in decompensated chronic liver disease (CLD) with an estimated prevalence of 20%-50% among hospitalized patients. AKI often heralds the onset of a downhill course in the natural history of CLD. Serum creatinine has several limitations as a stand-alone marker of AKI in patients with decompensated CLD. The concept of hepatorenal syndrome, the prototype of AKI in decompensated CLD, has evolved tremendously over recent years. There is emerging evidence of an additional "structural" component in the pathophysiology of hepatorenal syndrome-AKI, which was previously identified as a purely "functional" form of renal impairment. Lacunae in the existent biochemical arsenal for diagnosis and prognosis of AKI have fueled enthusiastic research in the field of novel biomarkers of kidney injury in patients with cirrhosis. The advent of these biomarkers provides a crucial window of opportunity to improve the diagnosis and clinical outcomes of this vulnerable cohort of patients. This review summarizes the dynamic concept of renal dysfunction in CLD and the available literature on the role of novel biomarkers of AKI in assessing renal function, identifying AKI subtypes, and predicting prognosis. There is special emphasis on the renal tubular injury marker, neutrophil gelatinase-associated lipocalin, the most exhaustively studied biomarker of AKI in the CLD population.

The urine albumin creatinine ratio is one of the predictors of acute kidney injury in hepatitis C-related cirrhotic hepatic encephalopathy

Background/objective

Hepatic encephalopathy (HE) is a main manifestation of acute decompensation in liver cirrhosis. Recently, systemic inflammation was proposed as a key mechanism in the development of acute kidney injury (AKI) in cirrhotic patients. The urine albumin creatinine ratio (UACR) is considered a marker of systemic inflammation in a variety of clinical settings. Here, we aimed to evaluate the role of the urine albumin creatinine ratio in the early prediction of AKI in HE.

Patients and methods

Sixty-seven consecutive patients presented with cirrhotic HE, and 59 age- and sex-matched cirrhotic patients with no history of HE served as controls. HE was defined and graded by the West Haven criteria. The severity of liver cirrhosis was evaluated by the Child-Turcotte-Pugh (CTP) score, and model for end-stage liver disease (MELD) score. The incidence of AKI that developed during hospital admission and the in-hospital mortality rate was estimated among HE patients. In addition, predictors of AKI were analyzed.

Results

The mean age of HE patients was 58.09±12.26 years; 36 (53.7%) were males, and 31 (46.3%) were females. Among HE patients, 16 (23.9%) developed AKI during hospital admission. The in-hospital mortality rate among HE patients was 22 (32.8%), the in-hospital mortality among HE-AKI patients was 81.3% (n=13/16), and UACR levels > 91.5 mg/g identified HE-AKI with 81.25% sensitivity (AUC = 0.85, P ≤ 0.001).

Conclusions

Patients with cirrhotic HE are at high risk of AKI. HE-AKI patients had a high rate of in-hospital mortality. Estimation of UACR at hospital admission is suggested for the early detection of patients with HE-AKI.

Novel Biomarkers of AKI in Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis that is associated with poor outcomes and decreased survival. The definition of AKI in cirrhosis is currently based on changes of serum creatinine levels with respect to baseline values. Differential diagnosis of the causes of AKI is of major relevance, considering that some causes of AKI, such as hepatorenal syndrome, have specific treatment options and different prognosis. Prediction of kidney function recovery and patients' survival is also crucial in this patient population to guide clinical decisions. AKI biomarkers in cirrhosis have emerged as a promising tool for differential diagnosis and prognosis in this situation. There are consistent data showing that some urine biomarkers, particularly neutrophil gelatinase-associated lipocalin, may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis. AKI biomarkers may constitute a useful tool for use in differential diagnosis, prognosis of renal function, and survival in patients with cirrhosis. This review focuses on the current state of knowledge and future perspective of novel biomarkers of AKI in cirrhosis.

Management of hepatorenal syndrome in liver cirrhosis: a recent update

Hepatorenal syndrome (HRS) is a serious form of renal dysfunction in patients with cirrhosis and ascites. It is an important component of the acute-on-chronic liver failure (ACLF) syndrome. Significant recent changes in the understanding of the pathophysiology of renal dysfunction in cirrhosis include the role of inflammation in addition to hemodynamic changes. The term acute kidney injury (AKI) is now adopted to include all functional and structural forms of acute renal dysfunction in cirrhosis, with various stages describing the severity of the condition. Type 1 hepatorenal syndrome (HRS1) is renamed HRS-AKI, which is stage 2 AKI [doubling of baseline serum creatinine (sCr)] while fulfilling all other criteria of HRS1. Albumin is used for its volume expanding and anti-inflammatory properties to confirm the diagnosis of HRS-AKI. Vasoconstrictors are added to albumin as pharmacotherapy to improve the hemodynamics. Terlipressin, although not yet available in North America, is the most common vasoconstrictor used worldwide. Patients with high grade of ACLF treated with terlipressin are at risk for respiratory failure if there is pretreatment respiratory compromise. Norepinephrine is equally effective as terlipressin in reversing HRS1. Recent data show that norepinephrine may be administered outside the intensive care setting, but close monitoring is still required. There has been no improvement in overall or transplant-free survival shown with vasoconstrictor use, but response to vasoconstrictors with reduction in sCr is associated with improvement in survival. Non-responders to vasoconstrictor plus albumin will need liver transplantation as definite treatment with renal replacement therapy as a bridge therapy. Combined liver and kidney transplantation is recommended for patients with prolonged history of AKI, underlying chronic kidney disease or with hereditary renal conditions. Future developments, such as the use of biomarkers and metabolomics, may help to identify at risk patients with earlier diagnosis to allow for earlier treatment with improved outcomes.

Management of Liver Decompensation in Advanced Liver Disease (Renal Impairment, Liver Failure, Adrenal Insufficiency, Cardiopulmonary Complications)

Systemic complications often occur in patients with advanced liver disease. In particular, the development of renal complications (acute kidney injury, hepatorenal syndrome), acute-on-chronic liver failure, cardiopulmonary diseases, or relative adrenal insufficiency can be serious in patients with advanced liver disease and may determine the patient’s quality of life and prognosis. Therefore, the early diagnosis of possible complications is the key to the prompt initiation of specific treatments that can improve quality of life and survival. For this purpose, networking with reference centers where multidisciplinary units are available is essential so that every patient is evaluated in clinical discussions involving specialists from different fields.

Peritransplant Renal Dysfunction in Liver Transplant Candidates

Renal function is intricately tied to Model for End-Stage Liver Disease score and overall prognosis among patients with cirrhosis. The estimation of glomerular filtration rate (GFR) and etiology of renal impairment are even more magnified among cirrhotic patients in the period surrounding liver transplantation. Novel biomarkers including cystatin C and urinary neutrophil gelatinase-associated lipocalin have been demonstrated to more accurately assess renal dysfunction and aid in the diagnosis of competing etiologies. Accurately identifying the severity and chronicity of renal dysfunction among transplant candidates is an imperative component with respect to stratifying patients toward simultaneous liver-kidney transplantation versus liver transplantation alone.

[Kidney failure after liver transplantation]

One third of cirrhotic patients present impaired kidney function. It has multifactorial causes and has a harmful effect on patients' morbi-mortality before and after liver transplant. Kidney function does not improve in all patients after liver transplantation and liver-transplant recipients are at high risk of developing chronic kidney disease. Causes for renal dysfunction can be divided in three groups: preoperative, peroperative and postoperative factors. To date, there is no consensus for the modality of evaluation the risk for chronic kidney disease after liver transplantation, and for its prevention. In the present review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease to determine a risk stratification for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this setting, and highlight the indications of combined liver-kidney transplantation.

Do old urinary biomarkers have a place in the new definition of hepatorenal syndrome in the Egyptian cirrhotic patients? A single-center experience

Background

Hepatorenal syndrome is still a diagnosis of exclusion despite new classification.

Aims

To validate the accuracy of urinary neutrophil gelatinase-associated lipocalin, interleukin-18, and kidney injury molecule-1 in the new diagnostic criteria of hepatorenal syndrome in Egyptian patients with hepatitis C virus-related liver cirrhosis using serum creatinine as a gold standard test for acute kidney injury.

Methods

One-hundred twenty cirrhotic patients with ascites were recruited and divided into two groups depending on the presence or absence of renal impairment, and 40 age- and sex-matched cirrhotic patients without ascites used as controls participated in the study. Urinary biomarkers were measured and compared with conventional biomarkers used to assess kidney function (serum creatinine, estimated glomerular filtration rate).

Results

The mean urinary neutrophil gelatinase-associated lipocalin, interleukin-18, and kidney injury molecule-1 were statistically significantly higher in patients with hepatorenal syndrome and were found to be helpful in the early detection with cutoff values of 125 ng/ml, 34.8 pg/ml, and 3.1 pg/ml, respectively.

Conclusions

Urinary neutrophil gelatinase-associated lipocalin, interleukin-18, and kidney injury molecule-1 levels are higher in patients with cirrhotic ascites complicated by HRS-AKI using the new definition of HRS, but IL-18 has lower sensitivity and specificity for the prediction of HRS-AKI as compared to NGAL and KIM-1.

Role of Novel Kidney Biomarkers in Patients With Cirrhosis and After Liver Transplantation

Acute kidney injury (AKI) and chronic kidney disease (CKD) are important drivers of morbidity and mortality in patients with cirrhosis before and after liver transplantation (LT). In this review, we examine the role of novel kidney biomarkers for early recognition of kidney injury. Studies are limited by lack of reference standards, heterogeneous definitions of outcomes and biomarker cutoffs, and inconsistent diagnostic performance. Overall, a change in biomarker is more relevant than an absolute cutoff. Cystatin C and urinary neutrophil gelatinase-associated lipocalin (uNGAL) are the most studied candidate biomarkers and identify AKI or progression of AKI earlier than serum creatinine (sCr). Kidney injury molecule 1 and liver-type fatty acid-binding protein (L-FABP) also show potential. NGAL and interleukin 18 may play a role in differentiating acute tubular necrosis from other forms of AKI. Combining novel biomarkers with the Model for End-Stage Liver Disease score may assist prognosis. Persistent elevations in select markers (eg, NGAL) can portend irreversible injury. Several pretransplantation markers (including sCr) predict posttransplantation kidney dysfunction. Pretransplantation assessment of clinical factors (eg, age, diabetes) and novel markers (osteopontin and tissue inhibitor of metalloproteinases 1 [TIMP-1]) may predict renal kidney recovery after LT. Intraoperative changes in biomarkers predict early post-LT AKI. Prediction of CKD remains difficult, although a combination of biomarkers (eg, beta-2 microglobulin, CD40) is promising. Novel biomarkers have yet to replace sCr in guideline-based evaluation and management of kidney dysfunction in patients with cirrhosis. We propose a theoretical framework for practical incorporation of these biomarkers that considers patient characteristics (risk for irreversible injury), markers of functional and structural change, and assessment of the AKI-CKD continuum to identify patients at the highest risk for progressive kidney disease before and after LT.

Hepatorenal Syndrome Type 1: From Diagnosis Ascertainment to Goal-Oriented Pharmacologic Therapy

Hepatorenal syndrome type 1 (HRS-1) is a serious form of AKI that affects individuals with advanced cirrhosis with ascites. Prompt and accurate diagnosis is essential for effective implementation of therapeutic measures that can favorably alter its clinical course. Despite decades of investigation, HRS-1 continues to be primarily a diagnosis of exclusion. Although the diagnostic criteria dictated by the International Club of Ascites provide a useful framework to approach the diagnosis of HRS-1, they do not fully reflect the complexity of clinical scenarios that is often encountered in patients with cirrhosis and AKI. Thus, diagnostic uncertainty is often faced. In particular, the distinction between HRS-1 and acute tubular injury is challenging with the currently available clinical tools. Because treatment of HRS-1 differs from that of acute tubular injury, distinguishing these two causes of AKI has direct implications in management. Therefore, the use of the International Club of Ascites criteria should be enhanced with a more individualized approach and attention to the other phenotypic aspects of HRS-1 and other types of AKI. Liver transplantation is the most effective treatment for HRS-1, but it is only available to a small fraction of the affected patients worldwide. Thus, pharmacologic therapy is necessary. Vasoconstrictors aimed to increase mean arterial pressure constitute the most effective approach. Administration of intravenous albumin is an established co-adjuvant therapy. However, the risk for fluid overload in patients with cirrhosis with AKI is not negligible, and interventions intended to expand or remove volume should be tailored to the specific needs of the patient. Norepinephrine and terlipressin are the most effective vasoconstrictors, and their use should be determined by availability, ease of administration, and attention to optimal risk-benefit balance for each clinical scenario.

An Integrated Review of the Hepatorenal Syndrome

Among the complications of cirrhosis, hepatorenal syndrome (HRS) is characterized by having the worst survival rate. HRS is a disorder that involves the deterioration of kidney function caused primarily by a systemic circulatory dysfunction, but in recent years, systemic inflammation and cirrhotic cardiomyopathy have been discovered to also play an important role. The diagnosis of HRS requires to meet the new International Club of Ascites-Acute Kidney Injury (ICA-AKI) and Hepatorenal Syndrome-Acute Kidney Injury (HRS-AKI) criteria after ruling out other causes of kidney injury. At the time of diagnosis, it is important to start the medical treatment as soon as possible where three types of vasoconstrictors have been recognized: vasopressin analogs (ornipressin and terlipressin), alpha-adrenergic agonists (norepinephrine and midodrine) and somatostatin analogues (octreotide); all should be combined with albumin infusion. Among them, terlipressin and albumin are the first lines of treatment in most cases, although terlipressin should be monitor closely due to its adverse events. The best treatment of choice is a liver transplant, because it is the only definitive treatment for this disease.

Sequential changes in urinary biomarker levels in patients with cirrhosis and severe hepatorenal syndrome

Whether tubular injury develops in patients with acute kidney injury owing to hepatorenal syndrome (AKI-HRS) is controversial. We performed repeated measurements of biomarkers of tubular injury during a 14-day period in 60 patients with cirrhosis and AKI (34 with AKI-HRS meeting the classical definition of type 1 HRS and 26 with AKI owing to acute tubular necrosis, AKI-ATN). Nineteen of 34 patients had resolution of AKI-HRS, while the remainder had persistent AKI-HRS. The persistence of AKI-HRS was associated with remarkably high short-term mortality. There were no significant differences in urinary NGAL or IL-18 between patients with resolution vs those with persistent AKI-HRS throughout the 14-day period. By contrast, biomarker levels were significantly lower in AKI-HRS, even if persistent, compared to AKI-ATN. These findings are highly suggestive of lack of significant tubular injury in AKI-HRS and could be of value in the clinical decision between combined liver-kidney or liver transplantation alone in patients with cirrhosis and AKI candidates to transplantation.

Urinary neutrophil gelatinase-associated lipocalin: Acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) in liver cirrhosis is associated with poor clinical outcomes including an increased long and short-term mortality. The common type of AKI observed in patients with cirrhosis are prerenal AKI (PRA), hepatorenal syndrome (HRS) and acute tubular necrosis (ATN). Despite the growing knowledge and uniform definition for the diagnosis of AKI, there are several challenges including, early diagnosis and management. Precisely differentiating the type of AKI is critical, as therapies differ significantly. In this review, we summarize AKI in liver cirrhosis, their definition, pathophysiology and deficiencies of using the existing biomarker, serum creatinine. We outline the current clinical evidence on the novel biomarker urinary neutrophil gelatinase-associated lipocalin (uNGAL) and its potential role as a biomarker in the early detection, differentiation and prognostication of AKI. This review also briefly talks about other forthcoming biomarkers which hold promise in the management of AKI in liver cirrhosis.

Portal Hypertension and Ascites: Patient-and Population-centered Clinical Practice Guidelines by the Italian Association for the Study of the Liver (AISF)

Portal hypertension and ascites are two crucial events in the natural history of liver cirrhosis, whose appearance marks a downward shift in the prognosis of the disease. Over the years, several international and national societies have issued clinical practice guidelines for the diagnosis and management of portal hypertension and ascites. The present document addresses the needs of an updated guidance on the clinical management of these conditions. Accordingly, the AISF Governing Board appointed a multi-disciplinary committee of experts for drafting an update of the most recent EASL Clinical Practice Guidelines. The aim of this work was to adapt the EASL recommendations to national regulations and resources, local circumstances and settings, infrastructure, and cost/benefit strategies to avoid duplication of efforts and optimize resource utilization. The committee defined the objectives, the key issues and retrieved the relevant evidence by performing a systematic review of the literature. Finally, the committee members (chosen on the basis of their specific expertise) identified the guidelines' key questions and developed them following the PICO format (Population, Intervention, Comparison, Outcomes). For each of the PICO questions, the systematic review of the literature was made on the most important scientific databases (Pubmed, Scopus, Embase).

Kidney Failure after Liver Transplantation

One-third of patients with cirrhosis present kidney failure (AKI and CKD). It has multifactorial causes and a harmful effect on morbidity and mortality before and after liver transplantation. Kidney function does not improve in all patients after liver transplantation, and liver transplant recipients are at a high risk of developing chronic kidney disease. The causes of renal dysfunction can be divided into three groups: pre-operative, perioperative and post-operative factors. To date, there is no consensus on the modality to evaluate the risk of chronic kidney disease after liver transplantation, or for its prevention. In this narrative review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease in order to establish a risk categorization for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this context, and highlight the indications of combined liver–kidney transplantation.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Acute kidney injury and hepatorenal syndrome in cirrhosis

Acute kidney injury (AKI) in cirrhosis, including hepatorenal syndrome (HRS), is a common and serious complication in cirrhotic patients, leading to significant morbidity and mortality. AKI is separated into two categories, non-HRS AKI and HRS-AKI. The most recent definition and diagnostic criteria of AKI in cirrhosis and HRS have helped diagnose and prognosticate the disease. The pathophysiology behind non-HRS-AKI and HRS is more complicated than once theorized and involves more processes than just splanchnic vasodilation. The common biomarkers clinicians use to assess kidney injury have significant limitations in cirrhosis patients; novel biomarkers being studied have shown promise but require further studies in clinical settings and animal models. The overall management of non-HRS AKI and HRS-AKI requires a systematic approach. Although pharmacological treatments have shown mortality benefit, the ideal HRS treatment option is liver transplantation with or without simultaneous kidney transplantation. Further research is required to optimize pharmacologic and nonpharmacologic approaches to treatment. This article reviews the current guidelines and recommendations of AKI in cirrhosis.

Response to Terlipressin and Albumin Is Associated With Improved Liver Transplant Outcomes in Patients With Hepatorenal Syndrome

BACKGROUND AND AIMS

Although terlipressin and albumin are effective at treating acute kidney injury-hepatorenal syndrome (AKI-HRS), liver transplantation (LT) is the best treatment. However, it is unclear if an effective treatment with terlipressin and albumin improves post-LT outcomes in these patients. The aim of this study was to evaluate the impact of response to treatment with terlipressin and albumin on posttransplant outcomes in patients with AKI-HRS.

APPROACH AND RESULTS

We analyzed two cohorts of patients with cirrhosis listed for LT between 2012 and 2016: 82 patients who developed AKI-HRS before LT and were treated with terlipressin and albumin and 259 patients without AKI-HRS who received transplants during the study period (control group). After LT, patients were followed up until discharge, every month for the first 3 months, and every 3 months thereafter. Of the patients, 43 (52%) responded to terlipressin and albumin. Responders had a better 30-day transplant-free survival (60% vs. 33%, P = 0.006), longer LT waiting list time (37 vs. 17 days, P = 0.041), and lower Model for End-Stage Liver Disease score at the time of LT (23 vs. 29, P = 0.007). Among patients with AKI-HRS receiving transplant, nonresponders required renal replacement therapy (RRT) more frequently than responders (20% vs. 0%, P = 0.024). Nonresponders had a significantly higher incidence of chronic kidney disease (CKD) at 1 year after LT than responders (65% vs. 31%, P = 0.019). In multivariate analysis, nonresponse to terlipressin and albumin was found to be an independent predictor for CKD at 1 year after LT (subdistribution hazard ratio [SHR] = 2.76, P = 0.001), whereas responders did not have an increased risk (SHR = 1.53, P = 0.210).

CONCLUSIONS

In patients with AKI-HRS, response to terlipressin and albumin reduces the need for RRT after LT and reduces the risk of CKD at 1 year after LT.

Monitoring Renal Function and Therapy of Hepatorenal Syndrome Patients with Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis. Patients with cirrhosis can develop AKI due to different causes. Hepatorenal syndrome (HRS) is a unique cause of AKI occurring in patients with advanced cirrhosis and is associated with high short-term mortality. The differential diagnosis between different causes of AKI may be challenging. In this regard, new urine biomarkers may be helpful. Liver transplantation is the definitive treatment of patients with HRS-AKI. Vasoconstrictors and albumin represent the first-line pharmacologic treatment of HRS-AKI. This review summarizes current knowledge for the diagnosis and management of HRS in cirrhosis.